Disc drives are used as primary data storage devices in modern computer systems and networks. While very reliable, today's disc drives occasionally fail. In addition to causing computer system downtime, such disc drive failures can result in the loss of some or all of the data stored in the disc drive. Accordingly, disc drives commonly perform Predictive Failure Analysis (PFA) using Self-Monitoring, Analysis and Reporting Technology (SMART), to predict disc drive failure caused by the gradual decay of electrical and/or mechanical components of the disc drive. The primary goal of PFA is to predict when disc drive failure is imminent to allow the data stored in the disc drive to be archived.
PFA is generally performed during the operation of the disc drive by monitoring key disc drive attributes that are indicative of the health of the disc drive. Additionally PFA can be implemented by performing periodic self-diagnostic tests on the disc drive. Present methods of performing PFA in disc drives will predict imminent disc drive failure based upon errors associated with a single attribute (e.g., read errors, seek errors, fly-height errors, etc.). In these methods, errors corresponding to the single attribute are monitored and compared to a threshold value. When the errors exceed the threshold, a warning of imminent disc drive failure is provided to the user.
Clearly, it is critical that the PFA method utilized in the disc drive accurately predict imminent disc drive failure. However, it is also important that the method not be overly sensitive to indications of imminent disc drive failure. In other words, while it is important to correctly identify disc drives that are about to fail, it is also equally important to avoid falsely predicting an imminent failure when the disc drive is properly functioning.